ProgramNode(0...18)(
  [:a],
  StatementsNode(0...18)(
    [LocalVariableOperatorOrWriteNode(0...18)(
       (0...1),
       (2...5),
       RescueModifierNode(6...18)(
         CallNode(6...7)(nil, nil, (6...7), nil, nil, nil, nil, 0, "b"),
         (8...14),
         NilNode(15...18)()
       ),
       :a
     )]
  )
)
